This invention relates to axial flow compressors or turbines, such as those forming a part of a turbojet engine, and deals more particularly with a compressor or turbine construction having a removable stator vane providing easy access to a portion of the rotor for rotor balancing, inspection, repair or other purposes.
In the manufacture and use of turbojet engines and other turbomachines it is often necessary to gain access to a rotor for various different purposes, and generally there are usually only one or a very few critical portions of the rotor to which access is needed on a relatively frequent basis. The purpose of this invention is to provide a means permitting access to such a critical rotor portion without requiring any major disassembly of the machine.
For example, the turbine and compressor rotors of turbojet engines normally rotate at high rotational speeds so that very small changes in their mass distribution have significant effects on their dynamic balance. Such changes in mass distribution occur from a number of factors, such as erosion, accumulation of dirt, distortion of parts and engine washing and is essentially unavoidable, so that is becomes necessary to trim balance the rotors at relatively frequent intervals. In performing such trim balancing, the degree and angle of the unbalance is determined while the rotor in question is driven at design speed in the actual engine installation, and then balance weights are attached to the rotor in its balance plane to compensate for the measured unbalance. In the past, this attachment of balance weights has many times required a difficult and lengthy disassembly of the engine to gain access to the rotor balance plane. The removable stator vane of this invention is, therefore, particularly useful for providing the access needed to add trim balance weights to a rotor.
Also, the removable stator vane feature of this invention may be used to provide a port allowing inspection and/or repair of an adjacent array of rotor blades. For example, rotor blades may occasionally become damaged by foreign objects passing through the flow path and the port provided by the removable vane allows one set of rotor blades to be inspected for such damage and further allows the damaged blades to be blended in place by blending tools, such as files, abrasive wheels, small milling cutters and the like, passed through the access port.
Other objects and advantages of the invention will be apparent from the following detailed description of the preferred embodiment thereof.